1. Field of the Invention
The presently disclosed subject matter relates to a distal end hood for an endoscope and an endoscope system. More particularly, the presently disclosed subject matter relates to a distal end hood for an endoscope and an endoscope system in which intraluminal observations and treatments are performed by supplying a constant-pressure gas fed from an gas feed unit into a lumen of a subject being tested through an opening provided at a distal end portion of a flexible endoscope inserted into the lumen.
2. Description of the Related Art
Conventionally, medical diagnostics using an endoscope has been widely practiced in the field of medicine. In particular, an image pickup element, such as a CCD (charge-coupled device), is built into a distal end portion of an endoscope to be inserted into a body cavity to take an image of the interior of the body cavity. And, signal processing is performed using a processor unit to display the image on a monitor. Then, a doctor can observe and use this image for diagnosis or inserts a treatment instrument from a treatment instrument insertion channel to perform treatments, such as sample collection and polyp removal.
In laparoscopic surgery in which curative treatments are performed without conducting laparotomy in order to minimize invasion into a patient, a rigid endoscope for observation or a treatment instrument for performing curative treatments is introduced into a body cavity through a plurality of trocars punctured into the abdomen of the patient. At this time, a pneumoperitoneum unit for supplying a pneumoperitoneum gas into an abdominal cavity is used, in order to secure the visual field of the rigid endoscope and an area for operating treatment instruments.
When, for example, an insertion part of a flexible endoscope having flexibility is inserted into a lumen, such as a stomach or a large intestine, to perform intraluminal diagnoses or treatments, a treatment instrument is inserted into a lumen through a forceps channel (treatment instrument channel) of the flexible endoscope to perform curative treatments therein. Also, at this time, a constant-pressure feed gas, such as a carbon dioxide gas, is supplied into the lumen.
For example, Japanese Patent Application Laid-Open No. 2009-131467 describes a system in which a gas is introduced into a gas feed conduit within a pneumoperitoneum unit from a gas cylinder filled with a CO2 gas. In Japanese Patent Application Laid-Open No. 2009-131467, the gas feed conduit is configured so that the CO2 gas is supplied into an abdominal cavity through an pneumoperitoneum tube introduced into the abdominal cavity by way of a gas feeding guide tube (trocar) punctured into the abdominal cavity of a patient.
In addition, Japanese Patent Application Laid-Open No. 2005-287839 describes a system in which a tube for an abdominal cavity and a tube for a lumen are coupled with a gas feed unit, so that a carbon dioxide gas is supplied from the tube for an abdominal cavity into an abdominal cavity through a trocar and that the carbon dioxide gas is supplied from the tube for a lumen into a lumen through a treatment instrument channel.
Yet additionally, Japanese Patent Application Laid-Open No. 2006-280535 describes a system in which a gas is sprayed from a gas/water feed nozzle at a leading end of a gas feed tube to be connected to a gas feed conduit communicated with a cylinder through a coupling member.